The McCain campaign has launched one of its bluntest attack ads to date, evoking fear by using Joe Biden's words that if Obama is elected, "We're going to have an international crisis to test the mettle of this guy. I guarantee it's going to happen."

McCain TV ad: "Ladies and Gentlemen:"

UPDATE (10/27): The Obama campaign released a response ad to the McCain attack:

The Progess for America Voters fund tried to raise fears about John Kerry's ability to handle international crisis in this ad: